Beverage brewing machine

ABSTRACT

In a first embodiment, a beverage brewing machine has a reservoir in which water is heated, which is arranged upstream of a brewing unit and heatable by an electric heating device. At the bottom is an outlet valve which opens only on reaching a given water temperature so that the hot water flows through an outlet pipe downstream of the outlet valve from the reservoir over the upper surface of a product, preferably ground coffee or tea-leaves, contained in a brewing unit, from which it goes to a receptacle as a beverage after extraction of the product. Hot water from the reservoir can also be taken via a pipe along paths other than over the upper surface of the product into the receptacle. The pipe takes a siphon-like path, the vertex of which is far enough above the bottom of the reservoir so that hot water also flows via the pipe to the other path and not only over the upper surface of the product only when a certain level is reached in the reservoir. In a second embodiment, the hot water is conveyed along the other path by a brewing head that has main and secondary chambers.

The present invention relates to beverage brewing machines

In such beverage brewing machines, water can be heated by an electricheating device and can discharge out of the supply reservoir through anoutlet valve, which assumes its open position only upon attainment of adefined water temperature, into a brewing unit containing a product,preferably ground coffee or tea leaves, from where it is finally, afterextraction of the product, conveyed as a brewed beverage into a storingtank. In addition, the beverage brewing machine includes a conduitthrough which brewing water can propagate from the supply reservoir intothe storing tank also along a path other than through the upper surfaceof the product.

A beverage brewing machine of this type is known, for example, fromDE-A-27 14 736, wherein a time-responsive switch is provided for thepurpose of influencing the aroma or, respectively, the strength, whentea is prepared, which switch controls a valve time-responsively sothat, in the event that a defined quantity of brewing water has flowninto the sieve, this path will be closed, and brewing water is conveyedonly along another path, that means in this case past the sieve,directly into the storing tank. By predetermining the quantity of theproduct and the quantity of water used, the desired strength of thebrewed beverage can be adjusted, that means the brewing time at whichthe device is set is specific for a product used and has to be observedprecisely, because if the brewing time is chosen to be too short, thebeverage will not have the proper aroma, while it has a bitter taste ifthe brewing time was too long.

Further, EP-0 079 235 B1 discloses a coffee machine, wherein the brewingaction is performed by cold water flowing from a supply reservoir into acontinuous flow heater, where it is heated. The resulting brewing wateris conveyed through a feed pipe to a brewing tip, from which it exitsinto a brewing unit containing a product, preferably ground coffee, outof which the so prepared brewed beverage finally discharges into astoring tank. In this coffee machine, too, a valve device is providedwhich is controllable either manually or by electronic components sothat after a predeterminable brewing time, during which the brewingwater is allowed to propagate only through the upper surface of theground coffee into the storing tank, the brewing water discharges intothe storing tank also along another path, a so-called bypass channel.

The reason for deviating the brewing water upon expiry of a determinedbrewing time is to take positive effect on the taste of the brewedbeverage. Thus, it is known above all from the preparation of coffeethat a too long contact time between brewing water and ground coffeewill extract undesired essential oils, bitter substances, etc. from theground coffee. Apart from impairing the taste, these mentionedsubstances are aggressive to the stomach and, further, are to be blamedthat the coffee, when it cools in a cup or is kept on a warming platefor too long, will practically be `upset` in its taste, that means achemical reaction is caused which even shows in the coffee becomingmuddy. Because of the context between contact time and the extraction ofundesirable substances from the ground coffee, the problems describedwill be increased even more, the more cups of the brewed beverage areprepared by the brewing water taking its course along the upper surfaceof the product. Both known beverage brewing machines counteract thedescribed extraction of substances by having further brewing waterpropagate along another path into the storing tank after expiry of adefined brewing time which is equal to the contact time of brewing waterand product. This way, substantially less undesirable substances aredissolved out of the product. Of course, the quantity of the productmust be adjusted in relation to the mentioned quantity of brewing waterby taking into consideration the personal taste of the user of thebeverage brewing machine.

It is the shortcoming of both beverage brewing machines mentionedhereinabove that they include complicated valve devices, either operatedmanually or electronically, which are comparatively costly andintricate. In addition, both beverage brewing machines include movableparts which may get jammed due to contamination, or may fail to functionfor any other reasons.

A beverage brewing machine of the prior-art type is known from U.S. Pat.No. 4,056,050 which is provided with an upwardly open distributiondevice which can be mounted on its brewing unit and from which brewingwater propagates into the storing tank both through the upper surface ofthe product and along another path. The distribution device issubstantially composed of a main and a secondary chamber, and the entirebrewing water which is conveyed from the continuous flow heater throughthe feed pipe enters through the main chamber and is dispensed onto theproduct after having overcome a valve device controlling the flowpassage. Likewise, the brewing water can flow out of the main chamberinto the secondary chamber after having surmounted a wall. Brewing waterwhich discharges out of the main chamber meets the product, whilebrewing water which discharges from the secondary chamber flows offdirectly into the storing tank without getting into contact with theproduct. Owing to the open construction of the distribution device anddue to the flow of the brewing water being slowed down as a result ofthe construction of the valve device, the brewing water coolsconsiderably already prior to getting into contact with the product. Onthe one hand, this cooling results in a reduced use of the ground coffeeand, on the other hand, in a reduced quality of the brewed beverage asfar as taste and aroma are concerned.

Therefore, the object of the present invention is to provide a beveragebrewing machine in which, when preparing larger quantities of a brewedbeverage, the time of contact of brewing water and product does notbecome longer as the quantity of the brewed beverage grows, the need forcomplicated and movable valve devices being obviated, and without thebrewing water cooling in a way detrimental to the aroma.

This object is achieved in a beverage brewing machine in that theconduit takes a siphon-like course, in that the vertex of the conduit isdisposed so far above the bottom of the supply reservoir that onlystarting with a defined filling level in the supply reservoir, brewingwater discharges also through the conduit and not only through theoutlet pipe. If only so large an amount of water is introduced into thesupply reservoir heated by an electric heating device that the vertex ofthe conduit is not reached at all, the total quantity of heated Waterflows directly onto the ground coffee in the filter unit. It has shownin practical operations that the optimal vertex of the conduitcorresponds approximately to a number of three cups. Once the brewingwater stands above the vertex of the conduit, a certain portion flowsoff when the outlet valve is open. It does not flow through the uppersurface of the ground coffee into the filter unit, but it is conveyedinto the storing tank along the other path, that is a pipe acting as abypass.

The size of the brewing water portion which flows through the bypassinto the storing tank depends on the opening cross-section of thesiphon-like conduit. Likewise, the quantity which flows directly intothe filter unit through the outlet pipe can be determined by thecross-section of the outlet pipe. By properly choosing the cross-sectionof the outlet pipe, the siphon cross-section and the maximum vertex ofthe conduit, for instance, a coffee machine can be provided whichpermits always to make an optimal coffee beverage, be it for a small ora large number of cups. The coffee beverage has a good aroma and aproper colour but only few bitter constituents, and the ground coffee isalso used substantially.

To always obtain from beverage brewing machines of various capacities anaromatic but not bitter coffee, it is favourable that the openingcross-sections of outlet pipe and conduit be larger in a beveragebrewing machine which can make 12 cups of coffee maximally, for example,than in a beverage brewing machine which can make only 6 cups maximally.Of course, the level of the vertex of the conduit has to be adjusted tothe capacity of the beverage brewing machine in the same manner.

It is also achieved by the conduit that if, for example, 12 cups ofcoffee are to be prepared, only part of the 12 cups of water will passdirectly through the ground coffee, while a certain portion of brewingwater flows through the conduit past the filter unit into the brewingunit. From this results the advantage that the filter unit and, thus, apaper filter inserted therein can be reduced in size compared toconventional coffee machines, since the head of water in the paperfilter is less due to the reduced passage of water through the groundcoffee. In addition, this shortens considerably the drip-empty time ofthe filter.

In order to be able to influence manually the taste and strength in acoffee machine in which 12 cups can be prepared, yet on an average onlysix cups are made in the most frequent cases, it is favourable accordingto a further development of the invention that the siphon-like conduitis made of flexible material and is dimensioned sufficiently long sothat the vertex of the conduit in respect of the bottom of the supplyreservoir can be adjusted to various levels by the user of the beveragebrewing machine. Consequently, the user can achieve to vary the taste ofthe coffee in a simple fashion by the level-adjustable arrangement ofthe conduit. If, for instance, the vertex of the conduit is close to thebottom, brewing water will be introduced already after a very short timethrough the conduit into the storing tank so that a strong, but not inthe least bitter, coffee can be prepared. If, on the other hand, thevertex of the conduit is farther away from the bottom of the supplyreservoir, the ground coffee, in total, is exposed longer to the brewingwater, while now as before more tasty than bitter substances areextracted. Consequently, the higher the vertex of the conduit isarranged, the more bitter the coffee becomes with a given quantity ofcoffee.

It is particularly advantageous that water flows through the conduitonly starting with approximately 20% to 40% of the maximally admissiblequantity of water in the supply reservoir. It is safeguarded by thisarrangement that, when a small quantity of coffee is prepared, forexample three cups, the entire brewing water will flow through thebrewing unit so that the siphon-like conduit will not be activated atall in such a brewing action. Thus, the coffee almost is not dilutedand, therefore, has high concentrate values which exceed, or are equalto, 1.25 percentage by weight. With a brew for eight cups and 6.5 gground coffee per cup of coffee, the coffee is considered to be strongstarting from approximately 1.25 percentage by weight concentrate.Therefore, it is appropriate for a brew of four and more cups to branchoff part of the brewing water through the conduit in order to wet theground coffee by hot water exactly so long that bitter constituents arenot yet dissolved from the ground coffee.

Particularly good coffee results are obtained when the openingcross-section of the siphon-like conduit compared to the total openingcross-section of conduit and outlet pipe approximately ranges between35% and 50%, preferably amounts to 45%. Thus, the opening cross-sectionof the siphon-like conduit is slightly smaller than the openingcross-section of the outlet pipe, but this is also absolutely necessarywhen the capacity of the beverage brewing machine is more than six cupsapproximately. This necessity results from the following: since thesiphon-like conduit, once it was activated, acts so long until theentire supply reservoir is emptied, a too large opening cross-section ofthe siphon-like conduit would permit too much brewing water to bedispensed into the storing tank so that a correspondingly small amountof brewing water would get into direct contact with the ground coffee.The result would be coffee which is too thin. The ratio of openingcrosssections indicated in the further development of the presentinvention, eventually, represents a mean value so that good coffee of aroughly equal quality without appreciable bitter constituents can-bemade when one cup of coffee up to twelve cups of coffee is/are prepared.

In order to be able to individually adjust the coffee's quality and itstaste as desired by the operator of the machine, in still anotherfurther development of the present invention the conduit is providedwith a valve device governing the passage of the brewing water, butensuring a minimum passage. Such a valve device is advisable inparticular when a coffee machine is used which exhibits wide limits fromthe minimum to the maximum number of cups. In this case, the valvedevice can be adjusted to a defined number of cups in such a way thatthe taste of the coffee for the coffee consumer is almost always in theoptimum range. The minimum flow passage of the valve device should beset to an average number of cups so that, if more cups are requiredexceptionally, an increase of the opening cross-section is possible byactivating the valve device, the passage of brewing water through theground coffee being reduced as a result.

It is particularly favourable that the valve device can be adjusted bythe user of the beverage brewing machine within limits so that, at asufficient filling level, 10% to 40% of the brewing water can dischargethrough the siphon-like conduit after the outlet valve is opened.

To ensure that the brewing water which discharges through the conduitinto the storing tank reaches the storing tank in a sufficiently hotcondition, it is favourable that the conduit extends through the supplyreservoir. It is achieved by this arrangement that as long as water isheated in the supply reservoir, the brewing water which flows throughthe conduit reaches the storing tank at a higher temperature than thebrewing water which flows through the ground coffee.

It is proposed in a second embodiment of the present invention that thebrewing tip in a beverage brewing machine provided with a continuousflow heater includes a main chamber and a secondary chamber which haveeach at least one outlet opening for the brewing water, the first outletopening conveying the brewing water directly to the upper surface of theproduct, while the second outlet opening conveys brewing water along theother path into the storing tank, that the feed pipe ends into the mainchamber, that a partition wall is arranged between the main chamber andthe secondary chamber which accumulates the brewing water being conveyedthrough the continuous flow heater into the main chamber for so longuntil the latter's level exceeds the upper edge of the partition wall,whereupon the supplied brewing water discharges also through thesecondary chamber and, hence, along the other path into the storingtank.

Alike the siphon-like conduit in the first embodiment, it is the purposeof the secondary chamber to ensure that only when the level of brewingwater in the main chamber has risen as a result of the constant inflowof brewing water out of the continuous flow heater up to the upper edgeof the partition wall due to the reduced discharge, overflowing into thesecondary chamber takes place and, thus, brewing water flows out of thesecond outlet opening into the storing tank as well, and flows no moreexclusively along the upper surface of the ground coffee. In this case,too, it can be determined by the quantity of water which the twochambers permit to store, by the feed performance of the continuous flowheater and by the proper dimensioning of the cross-sectional sizes ofthe outlet openings how much brewing water flows along the upper surfaceof the ground coffee and how much brewing water flows along the otherpath into the storing tank. This way, in turn, the taste of the coffeecan be adjusted rather precisely, more particularly as regards the shareof the bitter constituents in it. Neither this embodiment necessitatescomplicated or movable valve devices, there is need for only one brewingtip subdivided into a main chamber and a secondary chamber and having apartition wall and precisely defined cross-sections of the outletopenings. By choosing the height of the partition wall it can beachieved that, only after approximately the quantity of one cup up tothree cups of water is conveyed, a certain portion of brewing water mayflow over into the secondary chamber.

In order that the steam generation which is caused in the continuousflow heaters of the prior-art type when hot water is conveyed does notdevelop an excess pressure in the main and the secondary chambers whichwould have as a result that an increased quantity of water is dispensedout of the outlet opening, it is suggested by the invention that thebrewing tip is in constant communication with the atmosphereirrespective of the brewing water level. Hence, the steam which isgenerally produced with a snoring noise may escape to the atmosphere sothat both the main chamber and the secondary chamber always remainpressureless during the operation of the coffee machine.

According to the present invention, the connection of the brewing tipwith the atmosphere is established by a pipe which penetrates the bottomof the brewing tip and the free end of which is disposed above the upperedge of the partition wall. It is thereby accomplished that brewingwater is not dispensed through the pipe but exclusively through the twooutlet openings of the brewing tip.

To prevent hot steam from escaping unusedly through the pipe, the pipeis arranged in the main chamber close to the first outlet openingaccording to the invention. When hot steam exits from the pipe, theground coffee which is disposed beneath the first outlet opening iswarmed up by the steam so that it is preheated, and the brewed beveragealso becomes hotter in general. Expediently, the cross-section of thepipe is between 15 mm² and 30 mm². When the cross-section is smaller,the product overheats due to an excessive steam flow; when thecross-section is larger, the penetration of the product by hot steam isinsufficient. A pipe diameter of about 5 mm has proved to be expedientin conventional continuous flow heaters in the range of 900 to 1250watts. The product is protected, and bitter constituents are scarcelyreleased. With this dimensioning and when preparing eight cups of coffeewith a quantity of coffee of approximately 50 g, a final temperature inthe product between 87° C. and 93° C. results which is obtained by theinfusion of hot water plus the separate application of steam.

A good compromise between a sufficient use of the ground coffee and theshare in bitter constituents is obtained when the surface of the secondoutlet opening is smaller than the surface of the first outlet opening.

As far as the taste and the concentration of the brewed beverage overthe quantity range of one cup up to twelve cups is concerned, it hasproven particularly practicable that the dimensioning of first andsecond outlet opening is chosen such that after the first overflow ofbrewing water out of the main chamber into the secondary chamber onlyabout 10% to 40% of the brewing water which is then conveyed by thecontinuous flow heater will discharge through the second outlet opening.

The end of the conduit or the second outlet opening being directed tothe edge of the brewing unit and a channel being provided at the edgewhich forms the other path for the brewing water obviates the need for aseparate conveyance of the brewing water to the storing tank which wouldrequire additional components. Beside aesthetic advantages, costreduction is achieved as well.

The fact that the channel is formed by the outside of the filter insertand by the inner edge of the brewing unit in case that a water-permeablefilter is inserted into the brewing unit, with the width of the channelbeing determined by spacer elements and being sized such that theproduct is wetted laterally by the brewing water, it is accomplishedthat the brewing water which reaches the storing tank along the otherpath gets into contact with the lateral fringe areas of the product. Inparticular as far as coffee is concerned, the advantage is that thisfringe area, too, is better extracted by brewing water, since thebrewing water which exits from the first outlet opening will hardlyreach the fringe area of the ground coffee. Almost no undesirableproducts are dissolved out of the ground coffee, since the fringe areahas hardly been in contact with brewing water before, on the one hand,and since the contact time between brewing water and ground coffee isshortened anyway owing to the inventive brewing tip, on the other hand.It has shown in practical tests that the so-called concentrate in thebrewed beverage (which dictates the coffee's strength) can be augmentedby 10 to 15% in this improvement of the brewing tip according to thepresent invention. This effect is even enhanced by the fact that, withfilter inserts made of paper, also the concentrate which collects therewhen brewing water is only delivered out of the first outlet opening isfloated and, therefore, does not remain unused.

All the features mentioned before gain particular significance when thecontact surface between the brewing water, which exits from the secondoutlet opening and the fringe areas of the ground coffee, is increasedconsiderably by the channel extending over wide ranges or entirely alongthe periphery of the brewing unit.

In order to obtain a certain funnel effect when the brewing water isintroduced out of the second outlet opening into the channel, thechannel is provided with a collecting groove on its inlet side, which isopposite to the free end of the conduit or the second outlet opening.The collecting groove may also extend entirely or partly along theperiphery of the filter unit in order to take up brewing water whichejects intermittently out of the second outlet opening. Owing to thechannel terminating into the outlet opening of the brewing unit on theoutlet side, one single outlet on the brewing unit results, whichsimplifies the construction of the storing tank, since only one singleinlet must be provided, and, in addition, heat losses of the brewedbeverage are kept within limits.

In order to be able to make good coffee in a coffee machine also inpractice, it is favourable that the continuous flow heater delivers aquantity of 4 to 6 milliliters per second, that the total surface ofmain chamber and secondary chamber ranges between 20 cm² and 40 cm²,that the ratio of the surfaces of main chamber and secondary chamber isin the order of 4:1 to 8: 1, that the height of the partition wall is inthe range of 6 mm to 12 mm, that the surface of the first outlet openingranges between 7 mm² and 14 mm² and that the surface of the secondoutlet opening ranges between 4 mm² and 13 mm². Optimal coffee resultsare accomplished when the continuous flow heater supplies a quantity of4.5 milliliters per second at an electric output of 1250 watts, when thetotal surface of main chamber and secondary chamber approximatelyamounts to 30 cm² when the surface of the main chamber approximatelyamounts to 25 cm² and the surface of the secondary chamber approximatelyamounts to 4.5 cm², when the height of the partition wall is 8 mm, thesurface of the first outlet opening roughly amounts to 11 mm², and thesurface of the second outlet opening approximately amounts to 8 mm². Toprevent the water which flows into the secondary chamber from exitingtoo fast out of the second outlet opening, both the surface of thesecond outlet opening and the volume of the secondary chamber are lessthan the surface of the first outlet opening and the volume of theassociated main chamber. As a result, the quantity of water accumulatingin the second chamber, that means the quantity of brewing water whichflows through the channel--the so-called bypass quantity --, can bedetermined. Relatively high concentrate values are reached in spite ofsmall bypass portions; the losses in concentrate are insignificant(approximately 2.5%), the bitter constituents are negligible. The bypassportions can be varied by changing the volume portions of main chamberand secondary chamber as well as their outlet openings.

Another favourable embodiment of the present invention is that at leastone baffle is placed in the main chamber, each containing at least oneaperture which lies in about at the level of the bottom of the brewingtip. It is thereby achieved that brewing water which is conveyedintermittently from the continuous flow heater into the brewing tippasses over from the main chamber into the secondary chamber only whenthe mean brewing water level in the main chamber surmounts the upperedge of the partition wall.

In that embodiment, a valve is provided in the brewing tip which permitsto control the discharge, quantity of the brewing water along the otherpath. Thus, it is up to the user of the beverage brewing machine to makea brewed beverage with more bitter constituents or with less or almostno bitter constituents. That means the taste of the brewed beverage canbe predefined by the user. However, the valve can be closed only to suchextent that a portion of brewing water which discharges along the otherpath at the second outlet opening still amounts to a minimum of 30%,that means the valve cannot be closed entirely.

It is favourable that the valve is provided at the second outlet openingso that it's cross-section can be changed. The arrangement of the valveat the second outlet opening permits a particularly simple design of thevalve and ease of mounting it.

To obtain a valve which functions properly in a long useful life, it issuggested in a further improvement upon the present invention that thevalve is composed of a valve seat provided in the housing of the brewingtip and cooperating with a valve piston which can sealingly close thevalve seat, and that both the valve piston and the valve seat arefurnished with an aperture each, which apertures determine the openingcross-section of the valve depending on the degree they overlap eachother. The operation of such a slit-type valve is especially fail-safeand can be controlled at a small angle of rotation already from aminimum position (30% opening cross-section) to its maximum position(100% opening cross-section).

In order that the valve can be easily rotated even after a long time ofoperation and, nevertheless, does not become leaky when exposed to thegiven great variations in temperature, it is suggested in anotherimprovement upon the present invention that the valve seat is formed bya bore in which a cylindrical portion of the valve piston is sealedlyguided, that both the bore and the cylindrical portion are provided withan aperture each, and that on rotation of the valve piston about itslongitudinal axis the aperture of the valve piston will move intoalignment with the aperture of the valve seat. Thus, the valve is formedby a slide valve with a valve piston rotating in the sealing seat. Suchvalves with a sliding fit can be manufactured in particular withoutcomplicated seals and additional sealing elements. More particularly,valves made from a not too soft plastic material or ceramics have provenexpedient.

If it is desired that the actuating element be arranged at an easilyaccessible location on the beverage brewing machine, on the one hand,and the valve itself be arranged at another location on the beveragebrewing machine which permits ease of integration, on the other hand, itis proposed in another improvement upon the present invention that theactuating element is rotatable about an axis of rotation shifted inparallel to the longitudinal axis, and that the transmission of therotation of the actuating element to the valve piston is effected by aslide which eccentrically engages the former. Owing to this arrangement,the actuating element can be arranged separately from the valve in thebeverage brewing machine, and it can be operated mechanicallynevertheless.

A particularly simple lever gearing can be obtained in that the slidecontains a first and a second opening, a first pin provided outside thelongitudinal axis on the valve piston engaging into its first opening,and a second pin provided outside the axis of rotation on the actuatingelement engaging into its second opening. Owing to the pins which engageinto the openings after the assembly, a simple and quick coupling of theslide with the actuating element and with the valve piston isaccomplished. Due to the eccentric arrangement of the pins on theactuating element and on the valve piston, the rotary movementintroduced at the actuating element is converted into a straight-linedmovement on the slide which, subsequently, is converted into a rotarymovement on the valve piston again in order to control the valve. Alever gearing of this type affords ease of manufacture and, besides,permits the local separation of the actuating element from the valvepiston in the beverage brewing machine.

Since the valve governs the discharge of the brewing water out of thesecondary chamber through the second outlet opening, it is appropriateto guide the slide in the secondary chamber. As a result, the guidingdevices for the slide can be shaped directly at the secondary chamberwhich exists anyway. The slide must be arranged in the secondary chambersuch that, substantially, it does not get into contact with the exitingbrewing water in order to avoid additional seals between the conduit or,respectively, the secondary chamber and the slide. Especially simpleparts result when the brewing tip is made of plastics.

A valve device which exhibits a particularly clear lay-out and affordsease of operation is accomplished when the actuating element is guidedat the edge of the supply reservoir of the beverage brewing machine and,in addition, the supply reservoir extends substantially up to the upperedge of the beverage brewing machine. It is favourable that the supplyreservoir can be closed by a cover which covers the actuating elementtowards the outside. However, it is also possible in another embodimentthat the supply reservoir is closable by a cover and that the covercontains an opening through which the actuating element can be operatedfrom the outside. This design allows an operator a clear view and rapidaccess to the actuating element without having to open the cover of thesupply reservoir.

Two embodiments of the present invention are illustrated in the drawingsand will be described hereinbelow in more detail.

In the drawings,

FIG. 1 is a longitudinal cross-sectional view of a first embodimentaccording to the present invention, the other path for the brewing waterbeing formed by a conduit with a siphon-like course, and showing onlythe supply reservoir with the coffee filter of a beverage brewingmachine arranged therebeneath, and

FIG. 2 is a longitudinal cross-sectional view of a second embodiment ofthe present invention, wherein only the brewing tip containing the otherpath and the brewing unit of a beverage brewing machine are illustratedschematically, and

FIG. 3 is a so-called exploded view of a valve assembly fitted into thebrewing tip according to FIG. 2.

In FIG. 1, a section of a beverage brewing machine 1 is shown whichincludes above a brewing unit 2, a supply reservoir 3, on the bottom 4of which an electrically operated heating device 5 is arranged. Thus,the supply reservoir 3 in conjunction with the heating device 5represents an open boiler in which filled in water can be brought toboil. The heating device 5 is formed by a circularly extending heatingspiral 6 which is supplied with electric energy when a switch of thebeverage brewing machine is activated, which is not shown in thedrawing.

According to FIG. 1, further, a temperature control device 7 controllingthe temperature of the water of the supply reservoir 3 is arranged onthe bottom 4 outside the supply reservoir 3 which, once the water isheated to a sufficient temperature, interrupts the electric energysupply to the heating spiral 6. The supply reservoir 3 contains a fillopening 8 which is closable by a cover 9.

Also, an opening 10 is provided on the bottom 4 of the supply reservoir3 according to FIG. 1 which connects to an outlet valve 11 arrangedbeneath the bottom 4. The outlet valve 11 is formed by a thermostatvalve which does not open until the water, when heated, has reached apredetermined temperature, preferably its boiling temperature. An outletpipe 12 succeeds the outlet valve 11 and, as soon as the outlet valve 11has assumed its open position, allows the brewing water to be dispensedon the upper surface 53 of a product 13 introduced into the brewing unit2. Preferably, the product 13 is ground coffee which is filled into thebrewing unit 2 only after a water-permeable filter insert 14, preferablya paper filter, has been inserted into the receiving chamber 15 of thebrewing unit 2, which chamber tapers conically downwards.

Branching off from the outlet pipe 12 according to FIG. 1 is a conduit16 which has a siphon-like course 18, that means the conduit 16 extendsfrom its branch point 17 provided beneath the bottom 4 once more intothe chamber of the supply reservoir 3, from where it returns to thebottom 4 due to its siphon-like course 18, interrupts said bottom and,with its free end 19, is directed to the upper edge 20 of the brewingunit 2. At those points where the conduit 16 penetrates the bottom 4, ofcourse the conduit 16 must be shut off tightly against the openings 21,22 provided on the bottom 4.

According to FIG. 1, the vertex 23 of the siphon-like conduit 16 is at alevel h which roughly corresponds to a quantity of water of 20 percentto 40 percent disposed in the supply reservoir 3 of the maximum capacityof water which the supply reservoir 3 can take up. When a flexibleconduit 16 and a level-adjusting device not shown in FIG. 1 are used,the vertex 23 can be adjusted to different levels h by the user inasfaras the conduit 16 is sized to be sufficiently long.

According to FIG. 1, the supply reservoir 3 is embedded in a casing or,respectively, a housing 24 which is connected with a base 25. Of course,it is also possible that the siphon-like conduit 16 extends outside thesupply reservoir 3 in the same way. If necessary, the free end 19 of thesiphon-like conduit 16 can be provided with a valve device controllingthe passage of water, which is not illustrated in the drawing though.

Perpendicularly below the free end 19, a collecting groove 26 is shapedat the edge 20 of the brewing unit 2 which collects the brewing waterexiting at the free end 19 and conveys it to a channel 27 provided atthe edge 20 of the brewing unit 2, from where it is conveyed betweenfilter insert 14 and the wall 28 of the brewing unit 2 until it's bottom29, where it subsequently exits from the outlet opening 30 together withthe brewing water which entered through the upper surface 53 of theproduct 13. The ready brew is then dispensed through the outlet opening30 into a storing tank 31 provided beneath the outlet opening 30.

The collecting groove 26 can be shaped as a locally provided indentationin the edge 20 as is illustrated in FIGS. 1 and 2. However, it can alsobe provided as an annularly designed groove which extends in part orentirely in the edge's inner circumference of the filter unit 2, whichgroove, additionally, starting from the inlet, can have a gradient. Thechannel 27 is formed by the outside surface of the filter insert 14bearing against ribs 32 which project from the wall 28. The ribs 32 actas spacer elements in particular when a paper filter is used. Thus, thechannel 27 is formed by the outside of the filter insert 14 and theinner wall 28 of the brewing unit 2, on the one hand, and by the spacerelements 32 themselves, on the other hand. When a corresponding numberof spacer elements 32 is used along the wall 28, a variety of channels27 can be provided for the brewing water exiting from the end 19 of theconduit 16. When a form-stable filter insert 14, for example asieve-like metal filter, is used, already few spacer elements 32 aresufficient in order to provide a channel which circulates round thebrewing unit 2 and has a precisely defined width W.

The channel 27 includes a collecting groove 26 on its inlet side whichtakes up brewing water ejecting intermittently out of the conduit 16. Inthe event that several channels 27 are provided along the circumferenceof the brewing unit 2, or one single continuous channel 27 exists, thecollecting groove 26, too, extends correspondingly along thecircumference of the brewing unit 2.

The brewing unit 2 can be secured to the bottom side 33 of the housingor the casing 24, respectively, so as to be removable.

As can be seen in FIG. 1, in this embodiment the upper free end of thepaper filter 14 projects slightly beyond the collecting groove 26 inorder that, when brewing water flows through the conduit 16, it will notget into the interior 34 of the paper filter 14. However, the paperfilter 14 must not project upwardly so far that water which flows on thecollecting groove 26 will make the paper filter 14 collapse inwardly.

As far as the brewing unit 2 in FIG. 2 is concerned, it correspondsbasically to that one in FIG. 1 so that the one referred to in FIG. 2need not be dealt with more closely. Therefore, to avoid repetitions,like reference numerals have been assigned to like parts in the brewingunit 2.

FIG. 2 shows only a brewing tip 35 Which is provided on top of thebrewing unit 2. Said brewing tip 35 includes a feed pipe 36 whichcommunicates with a continuous flow heater not illustrated in thedrawing. In turn, the continuous flow heater communicates with a supplyreservoir not shown in the drawing which contains cold water during thebrewing action.

Since a coffee machine operating according to this principle has beenknown for long, as can be gathered from German patent application P 4108 631.7, the preparation and the transport of brewing water up to thebrewing tip 35 will not be referred to in detail herein. Finally, thebrewing water is conveyed to the feed pipe 36 at the brewing tip 35.

According to FIG. 2, the feed pipe 36 terminates into a main chamber 37provided in the brewing tip 35, however, at a level H with respect tothe bottom 38 of the main chamber 37 which is above the upper edge 39 ofa partition wall 40. The partition wall 40 confines the main chamber 37in FIG. 2 to the right and is disposed on the right of a first outletopening 41 which is provided roughly above the middle of the brewingunit 2 so that, when brewing water is dispensed out of the first outletopening 41, it flows directly on the upper surface 53 of the product 13disposed therebeneath.

Provided on the right hand of the partition wall 40 in FIG. 2 is asecondary chamber 42, which contains a second outlet opening 43 on thebottom 38 of the brewing tip 35 and which corresponds to the free end 19of the conduit 16 in FIG. 1. Therefore, also in this case, the brewingwater which exits from the second outlet opening 43 flows onto thecollecting groove 26 provided in the brewing unit 2, from where itpropagates through the channel 27, which like in FIG. 1 is formed of thepaper filter 14, the ribs 32 and the wall 28, finally into the outletopening 30 which is provided at the bottom end of the brewing unit 2,from where it, subsequently, enters through the inlet 44 into thestoring tank 31 disposed therebeneath.

According to FIG. 2, a pipe 45 is provided on the left hand of the firstoutlet opening 41 in the bottom 38, which pipe penetrates the bottom 38downwardly towards the atmosphere and which projects into the mainchamber 37 so far that it ends with its upper edge 46 above thepartition wall 40. Pipe 45 serves to vent the main and the secondarychamber 37, 42. Following the first outlet opening 41 is another valve47, by which the opening cross-section of the first outlet opening 41can be increased.

The mode of effect of the beverage brewing machines according to FIGS. 1and 2 is as follows:

When cold water is filled into the supply reservoir 3 of the beveragebrewing machine 1 according to FIG. 1, the filling level of which isindicated by the water-depth gauge, it can be noted that the water-depthgauge 48 is above the vertex 23 of the siphon-like extending conduit 16.As soon as the main switch (not shown) of the beverage brewing machine 1is actuated, the heating device 5 becomes operative since thetemperature control device 7 is short-circuited. Now the water in thesupply reservoir 3 is heated until it starts to boil, or, respectively,until the desired temperature is reached. Beginning from this point, thetemperature control device 7 interrupts the power supply to the heatingspiral 6. Simultaneously, the outlet valve 11 opens, and brewing waterdischarges via the outlet pipe 12 onto the upper surface 53 of theproduct 13 into the brewing unit 2.

Since the water-depth gauge 48 of the brewing water is above the vertex23 of the conduit 16, brewing water is also dispensed through theconduit 16 and the free end 19 into the collecting groove 26 of thebrewing unit 2. When the crosssections of outlet pipe 12 and conduit 16have been chosen correspondingly, it is ensured that a sufficient amountof pressure prevails at the inlet of the conduit 16 in order thatbrewing water can flow through the conduit 16.

The branch point 17 of the conduit 16 can also be connected directly onthe bottom 4 of the supply reservoir 3 with a temperature-controlledvalve of its own (not illustrated) so that the discharge of brewingwater, which otherwise is effected through the conduit 16, can beeffected through an own connection at the supply reservoir 3, instead ofby way of the valve 11.

The quantity of brewing water which gets into contact with the uppersurface 53 of the product 13 extracts the extraction materials, forexample from coffee, and then flows at the outlet opening 30 through theinlet 44 into the storing tank 31. Simultaneously, however, brewingwater flows through the channel 27 provided as a bypass to the outletopening 30. This portion of brewing water which, in the event of awaterpermeable filter insert 14, gets into contact with the groundcoffee 13 from said's lateral surface leads to effectively extract theground coffee in this area which, in the event that brewing water issupplied solely through the upper surface 53, will not result to thisdegree. Owing thereto, one can do with a reduced quantity of groundcoffee 13 when making coffee of a desired strength. Practically, thereis hardly any extraction of undesirable flavour materials, since thecontact times between the ground coffee 13 and the brewing water arereduced due to the channel 27 acting as a bypass.

This is because due to the separate discharge of the brewing water outof the supply reservoir 3, a smaller portion of brewing water isintroduced through the upper surface 53 of the product 13 than would bein case the conduit 16 did not exist. As a result, brewing water isapplied to the product 13 for a shorter period of time so that bitterconstituents and other products impairing the brew are not extracted.The brewing water penetrating the channel 27 extracts the product 13 inthe upper fringe area of the paper filter and also flows through theoutlet opening 30 out of the brewing unit 2 and, in doing so, mixes withthe extracting brew.

The higher the water-depth gauge 48 in FIG. 1 is, the greater portionsof brewing water pass through the conduit 16 and the channel 27. Thisportion of brewing water can amount to 10 to 40 percent approximately,depending on which water-depth gauge 48 prevails in the supply reservoir3.

If the water-depth gauge 48 in FIG. 1 is below the vertex 23, no brewingwater at all flows through the conduit 16, that means the entire brewingwater must pass the product 13 through said's upper surface 53. However,since in this case the extraction time, that means the time during whichthe product 13 is in contact with the brewing water, is still relativelyshort, undesirable materials are extracted from the product 13 only to alimited extent.

When the filter insert 14 is not water-permeable in the lateral areas ofthe ground coffee 13, admittedly, no extraction effect is accomplishedwith the portion of brewing water which flows through the channel 27,but it still remains that the contact time between the brewing water andthe ground coffee, favourably, is shortened due to the bypass effect ofthe channel 27 in connection with the conduit 16.

When the main switch of the beverage brewing machine 1 is actuated inFIG. 2, water is heated in the continuous flow heater not illustrated inFIG. 2 and, due to the effect of the resultant formation of steambubbles, is pumped upwardly in the feed pipe 36 until brewing waterenters over the edge 49 of the feed pipe 36 into the main chamber 37. Asis generally known, a continuous flow heater delivers brewing water inconformity with its heating power and the cross-section of its heatedpipe in more or less rapid intervals so that brewing water spillsabruptly over the upper edge 49. In the absence of a valve 47, aquantity of brewing water corresponding to the cross-section provided atthe first outlet opening 41 flows out of the first outlet opening 41onto the upper surface 53 of the product 13 disposed underneath.

However, since the cross-section of the first outlet opening 41 isdimensioned such that less brewing water is dispensed than is introducedthrough the feed pipe 36, the main chamber 37 fills slowly with brewingwater until a brewing water level 50 is reached which corresponds to theupper edge 39 of the partition wall 40. Subsequently, brewing waterenters also over the upper edge 39 of the partition wall 40 into thesecondary chamber 42, from where it propagates through the second outletopening 43 into the collecting groove 26 of the brewing unit 2, and fromthere it flows along the channel 27 to the outlet opening 30, where itis mixed with the brew and is dispensed into the storing tank 31 placedunderneath. It has already been explained hereinabove in the descriptionof FIG. 1 how the channel 27 causes further extraction of the groundcoffee so that there is no need to describe it once more at this point.

Due to the substantial formation of steam during the delivery of thebrewing water through the feed pipe 36, an excess pressure would becaused in the closed brewing tip, thus in the main and secondarychambers 37, 42, unless the pipe 36 was provided in the main chamber 37which terminates only above the water level 50, which extends throughthe bottom 38 and is connected to the atmosphere there. This preventsthe occurrence of a pressure increase in the main and secondary chambers37, 42, since pressure impacts are dispensed at once through the pipe 45to the atmosphere, an even discharge of brewing water out of the outletopenings 41, 43 being accomplished in dependence on the water level.Advantageously, the exit of hot steam at the pipe 35 is still used toheat the product 13 and the brewing unit 2 within certain limits so thatheat losses occurring when the brewing water passes through the product13 are compensated in part and, thus, sufficiently hot coffee reachesthe storing tank 31.

As can still be seen in FIG. 2, a baffle 51 rises from the bottom 38 andis provided with at least one aperture 52. The apertures 52 serve that auniformly high water level 50 adjusts on the left and the right handside of the baffle 51 in the main chamber 37. The purpose of the baffle51 itself is to catch brewing water which is injected at the upper edge49 of the feed pipe 36 and to convey it into the main chamber 37 inorder to always ensure that brewing water flows into the secondarychamber 42 only when the brewing water level 50 is indeed at the levelof the upper edge 39 of the partition wall 40.

Instead of the continuous flow heater not illustrated in FIG. 2, alsothe supply reservoir 3 together with valve 11 illustrated in FIG. 1could be used for heating the brewing water, from which reservoir theentire brewing water could be supplied to the main chamber 37 afteropening of the valve 11. In this case the dimensions of the two outletopenings 41, 43 and the size of the main and secondary chambers 37, 42would have to be adapted to the suddenly starting continuous supply ofbrewing water.

In the bottom part in FIG. 3, the brewing tip 35 described in FIG. 2 isillustrated partly in dash-dotted lines, into which, through the pipe36, the hot brewing water enters from the continuous flow heater notshown in the drawing through the inlet opening 79 into the main chamber37. The main chamber 37 is surrounded by a circumferential wall 107.Extending from the bottom 38 of the main chamber 37 upwardly is apartition wall 40 which, in conjunction with the bottom 81, forms thesecondary chamber 42 and which is bounded by the main chamber 37 up tothe upper edge 39. The main chamber 37 includes the inlet opening 79,rectangular in its cross-section, which is offset in height with respectto the bottom 38 of the main chamber 37. The main chamber 37 contains inits bottom 38 an opening 41 which conveys the brewing water directly tothe upper surface 53 of the product 13 according to FIG. 2. The inletopening 79 is arranged in the circumferential partition wall 107 of thebrewing tip 35.

As can be seen from FIG. 3 in addition, the secondary chamber 42includes on its bottom 81 a tubularly designed valve seat 55 whichreaches concentrically to the vertically extending longitudinal axis Yand which contains an aperture 58 in its wall 83. Succeeding the valveseat 55 downwardly is the outlet opening 43 shown in FIG. 2. Theexternal wall of the tubular valve seat 55 is provided with acylindrically extending peripheral surface 83 which is overlapped by atubular socket 84. The tubular socket 84 is disposed on the bottom sideof a cover 86 designed like a shell. This cover 86 engages with a collar87 into the inner edge 108 of the wall 107 and is in sealing abutmentthereon. This accomplishes closure of main chamber 37 and secondarychamber 42 which affords ease of mounting. The bottom 85 of the cover 86is placed so far above the inlet opening 79 and the partition wall 40that the brewing water is not inhibited to flow into the main chamber 37and, over the upper edge 39 of the partition wall 40, into the secondarychamber 42. The cover 86 limits the main and secondary chambers 37, 42so as to seal them towards the top.

The socket 84 in FIG. 3 is provided with a bore 89, into which the valvepiston 56 is inserted and engages with its cylindrically extendingportion 59 into the cylindrically formed valve seat 55 when the valvepiston 56 is fitted into the bore 89. Provided on the portion 59 of thevalve piston 56 is an aperture 57, which is formed corresponding to theaperture 58 from the top to the bottom, that is in parallel to thelongitudinal axis Y, and which, in the event that both apertures 57, 58are in alignment with each other in part or in full (not shown),releases the brewing water which entered the secondary chamber 42 to theexit so that this brewing water is allowed to discharge into the brewingunit 2 through the second outlet opening 43 which succeeds the valveseat 55 (FIGS. 2 and 3).

According to FIG. 3, knubs 90 which are evenly distributed along thecircumference of the bore 89 and are on the same level rise from thebore 89 concentrically to the longitudinal axis Y. These knubs 90 serveto axially secure the valve piston 56 in the bore 89 or, respectively,on the valve seat 55 after the valve piston 56 has been inserted intothe bore 89. In this case, the knubs 90 engage the collar 91 provided onthe valve piston 56 from behind so that the valve piston 56 is notpermitted to turn upwardly out of the bore 89, not even in the event ofa repeated rotation upon operation of the valve 54. Above the collar 91,rings 92 are provided which are dimensioned in respect of the internaldiameter of the bore 89 such that a seal joint is additionally formed atthis location. Also, the external diameters of the outside peripheralsurfaces of the rings 92 are sized such that they abut with a smallpreload on the wall of the bore 89 so that an automatic rotation of thevalve piston 56 due to vibrations acting upon the beverage brewingmachine 1 is prevented.

At its upper end, the valve piston 56 in FIG. 3 is furnished with a ring93 which, when the valve piston 56 is mounted in the bore 89, serves asa stop at the end surface 94 confining the bore 89 to the top.Succeeding the annular collar 93 upwards in FIG. 3 is a lever 95, whichis shaped at the valve piston 56 and at the top end surface of which anupwardly directed first pin 76 is formed. With the valve 54 mounted, thefirst pin 76 engages into a first opening 74 which is provided above thevalve piston 56 at a slide 66, the said opening being formed at aprojection 96 shaped laterally at the slide 66.

With the valve 54 mounted in the brewing tip 35, the slide 66 with itsportion 100 lies flatly in a recess 97 provided in the bottom 85 of thecover 86, the individual lateral wall portions 98 of the recess servingas a lateral boundary for the slide 66 so that the former isdisplaceable only in its displacing direction Z. The slide 66 isretained upwardly by the lower side of the upper cover (not illustrated)of the beverage brewing machine 1 in the recess 97. The bottom portionof the lateral wall 98 includes an extension 99, owing to which asufficient play is ensured for both the lever 95 and the projection 96when the slide 66 is displaced in its displacing direction Z. Followingthe front area 100 are steps 104 which serve that the slide 66 can beguided along the collar 87 outwardly to the second pin 77 of theactuating element 73. The step 102 serves as a stop for the slide 66 inthe direction Z. A second opening 75 is provided in the front portion105 of the slide 66 into which the second pin 77 engages in the mountedcondition of the valve 54. The second pin 77 is arranged eccentricallyon the actuating element 73 which, substantially, is of circular design,and which, in the mounted condition, is encompassed by a bore 78 formedin the cover 9 of a supply reservoir (not shown) of a beverage brewingmachine 1. The actuating element 73 comprises on its circumferencelocking elements 106, which are engaged from behind into a(nonillustrated) bore incorporated in the supply reservoir and therebyrotatably mount the actuating element 73 at the supply reservoir. As canbe seen in FIG. 3, the axis of rotation X has a distance A from thelongitudinal axis Y which corresponds to the distance between the valvepiston 56 and the actuating element 73. Due to the two pins 76, 77having the same distance from the elongated openings 74, 75, it ispossible to actuate the valve 54 by way of the slide 66. Thus, theposition of the actuating element 73 can be determined under functionaland creative points of view irrespective of the predefined position ofthe opening 43 (FIG. 2).

The mode of effect of the valve according to the present invention as inFIG. 3 in connection with the beverage brewing machine of FIG. 2 is asfollows:

When the valve 54 is closed, the slots 57, 58 overlap each other butslightly, that means the slot 57 is sealingly closed in the essentialarea by the valve seat 55 in such a way that only approximately 30% ofthe maximum opening cross-section are open. Admittedly, this positionallows brewing water to flow over the upper edge 39 of the partitionwall 40 into the secondary chamber 42 once the main chamber is filledwith brewing water. However, discharge of the brewing water through thevalve 54 to the free end 19 of the conduit 16 (FIG. 1) or, respectively,to the second outlet opening 43 (FIG. 2) takes place in a small quantityonly. This way, the major portion of brewing water flows through thefirst outlet opening 41 onto the upper surface 53 of the product 13according to FIG. 2. From this results a brewed beverage having acomparatively large amount of bitter constituents. To avoid repetitions,the other path 27 which the brewing water takes through the secondoutlet opening will be described hereinbelow.

When an operator desires a less bitter brew, for instance when makingcoffee, he/she may open the valve 54 farther by rotating the actuatingelement 73. In this case, the second pin 77 rotates and, through thesecond opening 75, entrains the slide 66 in its longitudinal direction.This causes the first pin 76, too, to displace by way of the first bore74 so that the valve piston 56 is rotated in the bore 89 and,simultaneously, in the valve seat 55 by the lever 95. In doing so, theoverlapping of the slot 57 with the slot 58 is enlarged such that thebrewing water in the secondary chamber 42 can be dispensed to a largerextent out of the secondary chamber 42 and, according to FIG. 2, canflow through the second outlet opening 43 into the collecting groove 26of the filter unit 2. Naturally, the brewing water takes the same coursethrough the second outlet opening 43 also at a minimum valve position.

After the brewing water has entered the collecting groove 26, it isconveyed through the channel formed between the paper filter 14, theribs 32 and the inner wall 28 of the filter unit 2, to the outletopening 30, the channel being also part of the other path 27. Part ofthe bypass water can also propagate through the outside surface of thepaper filter 14 into the product 13 and extract it additionally from theoutside area so that the product 13 is used better, without anyappreciable bitter materials reaching the brewed beverage.

The larger the overlapping of the slots 57, 58 is, the greater theamount of brewing water is which discharges from the secondary chamber42, and the smaller the amount of brewing water is which flows directlythrough the upper surface 53 of the product 13 (FIG. 2). The valve 54 isrelatively insusceptible to calcareous deposits because the outside wallof the cylindrically extending portion 59 of the valve piston 56 is inclose contact with the inner wall of the valve seat 55, and because ofthe rigid design of the recessed portion 59. That means, an operator caninfluence the taste of the brewed beverage by adjusting the valve 54 soas to have more or less bitter constituents in the brew.

Of course, instead of the valve described hereinabove, it is alsopossible to integrate any other valve into the beverage brewing machineshown in FIG. 1 to control the discharge out of the conduit 16.

We claim:
 1. A beverage brewing machine comprising storing tankstructure, brewing structure, supply reservoir structure, an electricheating device coupled to said supply reservoir structure, said supplyreservoir structure having a bottom and being adapted to receive waterto be heated by said electric heating device, outlet valve structurecoupled to said supply reservoir structure for controlling flow ofbrewing water out of said supply reservoir structure onto the uppersurface of a product, preferably ground coffee or tea leaves, containedin said brewing structure, from which, after extraction of the product,the so prepared brewed beverage finally discharges into said storingtank structure, siphon-like conduit structure coupled to said supplyreservoir structure through which brewing water can propagate also alonga path in said brewing structure out of said supply reservoir structureinto said storing tank structure, other than through the upper surfaceof the product, said siphon-like conduit structure having a vertexdisposed above said bottom of said supply reservoir structure, suchthat, only starting with a defined filling level in said supplyreservoir structure, brewing water discharges also through saidsiphon-like conduit structure and not only through the upper surface ofthe product in said brewing structure.
 2. The beverage brewing machineof claim 1 wherein said siphon-like conduit structure is made of aflexible material and is sized sufficiently long so that said vertex ofsaid conduit in respect to said bottom of said supply reservoirstructure can be adjusted to various levels by the user of said beveragebrewing machine.
 3. The beverage brewing machine of claim 1 whereinbrewing water flows also through said siphon-like conduit structure onlystarting with a filling level of at least 20% of the maximum capacity ofwater in said supply reservoir structure.
 4. The beverage brewingmachine of claim 3 and further including outlet pipe structure connecteddownstream of said outlet valve structure, the opening cross-section ofsaid siphon-like conduit structure in relation to the openingcross-section of said outlet pipe structure being between 35% and 50%.5. The beverage brewing machine of claim 1 wherein said siphon-likeconduit extends through said supply reservoir structure.
 6. A beveragebrewing machine comprising supply reservoir structure for receiving coldwater, heater structure coupled to said supply reservoir structure forheating cold water flowing out of said supply reservoir structure,distribution structure, brewing structure having an outlet opening,storing tank structure for communication with said outlet opening ofsaid brewing structure, feed pipe structure for conveying brewing waterfrom said heater structure to said distribution structure, saiddistribution structure containing partition wall structure, saidpartition wall structure subdividing said distribution structure into amain chamber and a secondary chamber, the entire brewing water flowingfrom said feed pipe structure into said main chamber, a first outletopening in said main chamber and a second outlet opening on the oppositeside of said partition wall structure from said first outlet opening insaid secondary chamber, brewing water, on the one hand, flowing fromsaid distribution structure through said first outlet opening onto theupper surface of a product, preferably tea leaves or ground coffee,contained in said brewing structure, from which, after extraction of theproduct, the so prepared brewed beverage finally discharges into saidstoring tank structure, and brewing water, on the other hand, can alsoflow from said distribution structure through said second outlet openingafter having surmounted said partition wall structure, this portion ofthe brewing water propagating along a path other than through the uppersurface of the product into said brewing structure, said distributionstructure having closed chamber structure, and vent pipe structure formaintaining said closed chamber structure in constant communication withthe atmosphere, said vent pipe structure penetrating the bottom of saidclosed chamber structure and having a free end which is disposed abovethe upper edge of said partition wall structure, said pipe ventstructure being fitted in said main chamber adjacent said first outletopening.
 7. The beverage brewing machine of claim 6 wherein the surfaceof said second outlet opening is smaller than the surface of said firstoutlet opening.
 8. The beverage brewing machine of claim 7 wherein thedimensions of said first and second outlet openings are such that afterthe first overflow of brewing water out of said main chamber into saidsecondary chamber, 10% to 40% of the brewing water which is thendelivered to said main chamber discharges through said second outletopening.
 9. The beverage brewing machine of claim 6 wherein the end ofsaid second outlet opening is directed to a peripheral edge of saidbrewing structure, and further including channel structure at saidperipheral edge for forming said other path for the brewing water. 10.The beverage brewing machine of claim 9 and further including awater-permeable filter insert containing the product for disposition insaid brewing structure, said channel structure being formed by theoutside of said filter insert and by the inner edge of said brewingstructure, and spacer structure for determining the width (W) of saidchannel structure, said spacer structure being sized such that theproduct in said filter insert is wetted laterally by the brewing water.11. The beverage brewing machine of claim 10 wherein said channelstructure extends over at least a majority of the circumference of saidperipheral edge of said brewing unit.
 12. The beverage brewing machineof claim 11 wherein on the inlet side, said channel structure includescollecting groove structure which extends beneath the upper edge of saidfilter insert and which is opposite said second outlet opening and, onthe outlet side terminates into said outlet opening of said brewingstructure.
 13. The beverage brewing machine of claim 6 wherein saidheater structure delivers water at a rate of 3.5 to 6 millimeters persecond, the total surface area of said main chamber and said secondarychamber is between twenty and forty square centimeters, the ratio of thesurface areas of said main chamber and said secondary chamber is in theorder of 4:1 to 8:1, the height of said partition wall structure is inthe range of six to twelve millimeters, the surface area of said firstoutlet opening ranges between seven and fourteen square millimeters, andthe surface area of said second outlet opening ranges between four andthirteen square millimeters.
 14. The beverage brewing machine of claim13 wherein said heater structure supplies a quantity of about 4.5milliliters of water per second at a power of about 1250 watts, thetotal surface of said main chamber and said secondary chamber isapproximately thirty square centimeters, the surface area of said mainchamber amounts about twenty-five square centimeters and the surfacearea of said secondary chamber amounts to about 4.5 square centimeters,the height of said partition wall is about eight millimeters, thesurface area of said first outlet opening is about eleven squaremillimeters, and the surface area of said second outlet opening is abouteight square millimeters.
 15. The beverage brewing machine of claim 6and further including at least one baffle in said main chamber, saidbaffle containing at least one aperture which lies about at the level ofthe bottom of said distribution structure.
 16. The beverage brewingmachine of claim 6 and further including valve structure in saiddistribution structure which permits control of the discharge of brewingwater along said other path.
 17. The beverage brewing machine of claim16 wherein said valve structure controls the passage of brewing water,but always ensures a minimum passage.
 18. The beverage brewing machineof claim 16 wherein said valve structure can be adjusted by the user ofthe beverage brewing machine within such limits that, at a sufficientfilling level, 10% to 40% of the brewing water is dispensed through saidsecond outlet opening.
 19. The beverage brewing machine of claim 16wherein said valve structure controls the cross-sectional size of saidsecond outlet opening and is provided at said second outlet opening. 20.The beverage brewing machine of claim 19 wherein said valve structure iscomposed of valve seat structure in the housing of said distributionstructure and a valve piston for sealingly closing said valve seatstructure, said valve piston and said valve seat structure each beingfurnished with an aperture, said apertures determining the openingcross-section of said valve depending on the degree they overlap eachother.
 21. The beverage brewing machine of claim 20 wherein said valveseat structure is formed by a bore and said valve piston has acylindrical portion which is sealedly guided in said bore, each of saidbore and said cylindrical portion being provided with a said aperture,and rotation of said valve piston about its longitudinal axis (Y) isadapted to place said aperture of said valve piston in alignment withsaid aperture of said valve seat structure.
 22. The beverage brewingmachine of claim 21 and further including actuating structure forrotating said valve piston about its longitudinal axis (Y) to controlsaid valve structure.
 23. The beverage brewing machine of claim 22 andfurther including slide structure which eccentrically engages said valvepiston, said actuating structure being rotatable about an axis ofrotation (X) shifted in parallel to said longitudinal axis (Y), and thetransmission of rotation of said actuating structure to said valvepiston being effected by said slide structure.
 24. The beverage brewingmachine of claim 23 wherein slide structure includes first and secondapertures, said valve piston includes a first pin outside saidlongitudinal axis (Y) of said valve piston engaging said first aperture,and said actuating structure includes a second pin outside the axis ofrotation (X) of said actuating structure engaging said second aperture.25. The beverage brewing machine of claim 22 wherein said distributionstructure includes a cover, and guide structure for guiding said slidestructure at said cover of said distribution structure.
 26. The beveragebrewing machine of claim 22 wherein said supply reservoir structureextends substantially up to the upper edge of said beverage brewingmachine, and said actuating structure is guided at the upper edge ofsaid supply reservoir structure.
 27. The beverage brewing machine ofclaim 26 wherein said supply reservoir structure includes coverstructure which covers said actuating structure.
 28. The beveragebrewing machine of claim 26 wherein said supply reservoir structureincludes cover structure, said cover structure containing an openingthrough which said actuating structure is operable from the outside. 29.A beverage brewing machine comprising supply reservoir structure forreceiving cold water, heater structure coupled to said supply reservoirstructure for heating cold water flowing out of said supply reservoirstructure, distribution structure, brewing structure having an outletopening, storing tank structure for communication with said outletopening of said brewing structure, feed pipe structure for conveyingbrewing water from said heater structure to said distribution structure,said distribution structure containing partition wall structure, saidpartition wall structure subdividing said distribution structure into amain chamber and a secondary chamber, the entire brewing water flowingfrom said feed pipe structure into said main chamber, a first outletopening in said main chamber and a second outlet opening on the oppositeside of said partition wall structure from said first outlet opening insaid secondary chamber, brewing water, on the one hand, flowing fromsaid distribution structure through said first outlet opening onto theupper surface of a product, preferably tea leaves or ground coffee,contained in said brewing structure, from which, after extraction of theproduct, the so prepared brewed beverage finally discharges into saidstoring tank structure, and brewing water, on the other hand, can alsoflow from said distribution structure through said second outlet openingafter having surmounted said partition wall structure, this portion ofthe brewing water propagating along a path other than through the uppersurface of the product into said brewing structure, and valve structurein said distribution structure which permits control of the discharge ofbrewing water along said other path, said valve structure controllingthe cross-sectional size of said second outlet opening and beingprovided at said second outlet opening.
 30. The beverage brewing machineof claim 29 wherein said valve structure is composed of valve seatstructure in the housing of said distribution structure and a valvepiston for sealingly closing said valve seat structure, said valvepiston and said valve seat structure each being furnished with anaperture, said apertures determining the opening cross-section of saidvalve depending on the degree they overlap each other.
 31. The beveragebrewing machine of claim 30 wherein said valve seat structure is formedby a bore and said valve piston has a cylindrical portion which issealedly guided in said bore, each of said bore and said cylindricalportion being provided with a said aperture, and rotation of said valvepiston about its longitudinal axis (Y) is adapted to place said apertureof said valve piston in alignment with said aperture of said valve seatstructure.
 32. The beverage brewing machine of claim 31 and furtherincluding actuating structure for rotating said valve piston about itslongitudinal axis (Y) to control said valve structure.
 33. The beveragebrewing machine of claim 32 and further including slide structure whicheccentrically engages said valve piston, said actuating structure beingrotatable about an axis of rotation (X) shifted in parallel to saidlongitudinal axis (Y), and the transmission of rotation of saidactuating structure to said valve piston being effected by said slidestructure.
 34. The beverage brewing machine of claim 32 wherein saidsupply reservoir structure extends substantially up to the upper edge ofsaid beverage brewing machine, and said actuating structure is guided atthe upper edge of said supply reservoir structure.
 35. The beveragebrewing machine of claim 34 wherein said supply reservoir structureincludes cover structure, said cover structure containing an openingthrough which said actuating structure is operable from the outside.